ZOOLOGY 



CHAPTER I. 

 INTRODUCTION. 



1. Nature presents to man, as he looks upon it, a great and 

 interesting variety of material objects. Each member of the 

 race gathers in his lifetime, by means of experience and infer- 

 ence, a certain limited knowledge of these objects and of the 

 changes to which they are subject. The knowledge, thus col- 

 lected and systematized in the course of the history of the 

 human race, constitutes the so-called Natural Sciences. Every 

 one of us, whether he deliberately chooses or not, must be in 

 some degree a natural scientist. The beauty and interest of 

 the work has attracted and charmed thousands of people of 

 all conditions, in all parts of the world. 



We commonly speak of material objects as either living or 

 non-living as organic and inorganic. The study of living 

 things in all their relations we call Biology. Physics and Chem- 

 istry are often considered as clealing exclusively with inor- 

 ganic matter, and are therefore placed in contrast with Biology. 

 Their principles apply, however, in ttie realm of living things 

 just as truly as in the non-living, and one must not imagine 

 because of this antithesis that the phenomena of life can be 

 explained apart from chemical and physical laws. The term 

 Biology was first introduced about the beginning of the nine- 

 teenth century, and is intended to express the fact that plants 

 and animals are similar in their most essential structure and 

 activities. The term Natural History is sometimes used 

 synonymous with Biology. 



2. Zoology. Owing to the fundamental likeness of all 

 living matter, there is great theoretical difficulty in distinguish- 

 ing between the plant and animal kingdoms. The practical 



